Propulsion of water craft and aircraft



31, 1929. v, o c -m ss 1,741,238

1 morupsrou. or WATERCRAFT AND AIRCRAFT Filed July so. 1927 2 Sheets-Sheet '1' F194 7 (w A own/rm OMN Q ATTORNE Dec. 31, 1929. p, v, o s 1,741,238

- PROPULSION or wunncmr'r AND AIRCRAFT Filed July 30. 1927 2 Sheets-Sheet 2 B) a 0 TTORNEY Patented Dec. 31, 1929 UNITED STATES I PATENT OFFICE PROPULSION OF WATER CRAFT AND AIRCRAFT Application filed July 30, 1927, Serial No. 209,578, and in Great Britain August 26, 1926.

This invention relates to the propulsion of watercraft and aircraft.

The principal objects of the invention are to provide apropelling apparatus or propelling unit that may be located in any part of the ship or vessel to be propelled, tohouse the apparatus or unit within the contour of the hull where it is not likely to be damaged, to eliminate propeller noises and vibration, to abolish racing in heavy seas, and to obtain full eliiciency astern aswell as ahead.

These and other objects I attain by so constructing and arranging a propelling apparatus in the vessel as to create an expanding helical flow of the surrounding fluid along. an axis that is disposed at an angle (not parallel) to the longitudinal axis of said vessel, the fluid being discharged tangential- V ly from the helix (or helices).

There may be a plurality of impeller units each constructed and arranged in the manner stated.

In its simplest form the apparatus consists of a propeller unit of two main integers, namely, a casing of concentricallyexpanding shape with a tangential inlet and outlet opening, and an' impeller rotatable in the casing to create a helical flow that expands in the direction of its motion. Where saving of weight is important the base of the impeller (or each impeller) may be made hollow and watertight so as to ffloat the impeller in the fiuid contained within the casing.

Said casing, which may be incorporated in the vessels structure as part of the hull, is in the shape of a cone, frustum of a cone, paraboloid, hemisphere or the like in which an expanding helix (or helices) can be created by the rotation therein of the impeller.

Two or more units, each comprised of a casing and impeller, as aforesaid, may be employed and arranged in various ways in the vessel. For example, two units may be aligned and disposed athwartship with the apertures in their casings open to the fluid through the bottom of the vessel; or several units may be disposed within the vessel along the sides thereof and at intervals apart.

Preferably, the impeller casing or each impeller casing is of substantially conical shape with a triangular aperture in its peripheral side to provide an inlet at or near the apex 18f the casing and an outlet at or near the ase.

Where reversibility is required without changing the direction of rotation of the impeller, means are provided by which the direction of discharge of the fluid from the casing or each casing can be reversed while the impeller therein continues to rotate al- 66 ways in one direction. Said means consists,

or may consist, of a hinged flap or butterfly valve controlling the discharge portion of the aperture in the casing.

By way of example, three modes of carrying the invention into practice are shown on the accompanying drawing whereon Fig. 1 is a diagrammatic view illustrating the principle of the invention;

Fig. 1 shows diagrammatically a crosssectional view of Fig. 1 taken at right angles to the axis of rotation, illustrating the principle of the invention. It will be understood that the four-bladed impeller shown in Fig. 1 is one form of impeller which may be used, and that various other forms of impellers may be employed which are well known to persons familiar with the art;

Fig. 2 is a plan of what may be termed a direct reversible twin unit propelling apparatus;

Fig. 2 shows diagrammatically a crosssectional view of Fig. 2, taken at right angles to the axis of rotation through one of the casings and impeller shown in Fig. 2. For purposes of simplicity only a two-bladed impeller is shown, but it will be understood that this two-bladed impeller asshown is one form of impeller which may be used, and that various other forms of impeller may be employed which are well known to persons familiar with the art;

Fig. 3 is a diagrammatic elevation showing a propelling apparatus comprised of a number of individual units disposed along the sides of a vessel;

Fig. 4 is a partial plan corresponding to Fig. 3;

Fig. 5 is a fragmentary sectional elevation M g of a twin unit apparatus similar to that shown by Fig. 2 but provided with special reversing equipment; and

Fig. 6 is an inverted view of the same. The underlying idea of the invention is the propulsion of a vessel by means of a fluid helix formed by the rotation of an impeller in a recess or casing of concentrically I expanding shape located in the vessel or incorporated in the vessels structure as part of the hull and having an aperture open to the surrounding fluid.

If a concentrically expanding casing (such as the cone-shaped casing 7 in Fig. 1) has an expanding aperture (8) in its peripheral wall open to the surrounding fluid (water or air and if a suitably shaped impeller be rotated therein, then a stream of the fluid will be caused to enter the aperture at or near the apex of the casing, will be impelled along an expanding helix within the casing about the axis thereof, and will be discharged tangentially from the aperture at or near the base of the casing to exert a reactive thrust. The motion of the stream of fluid is repre sented by the arrows in 1, from which it will be observed. that the fluid is dis charged at the large end of the aperture with the maximum velocity, the velocity of discharge decreasing successively towards the apex of the aperture and becoming a minus quantity at a point about one-third of the distance from the base. The rotation of the impeller within the casing causes an expanding helical flow of which the discharge stream is .an expression, the inflow taking place in the same direction as the discharge but the fluid entering the casing, between the apex of the aperture and the neutral point described.

In order to utilize the thrust caused by the discharge of the fluid from the casing for the propulsion of a vessel, it is only necessary so to arrange the casingin the vessel with. its aperture open to the surronndingfluid that the direction. of discharge is parallel or substantially parallel to the longitudinal. of the vessel, that is, to the direction of motion of the vessel. Under these conditions the thrust created by the discharge of the fluid from the casing will be in a direction either sternward or forward according to the direction of rotation of the impeller, and as the vessel attains motion of translation in consequence of that thrust the kinetic energy of the surrounding fluid, which is in relative motion to the vessel, is made to aid the helical flow. The apparatus can be disposed in various ways to satisfy the required conditions which imply that the axis of the expanding fluid helix must be at an angle (not parallel) to the vessels direction of motion. The angle may be a right angle or some other angle depending upon the shape of the casing that experience shows to be most suitable to onsure the maximum thrust in a fore and aft direction.

In Fig. 1 the aperture 8 in the casing 7 is shown as being triangular in shape and ex tending from the apex to the base of the easing, but the aperture can be varied in shape and size to suit the vessels contour, the output or quantity of fluid discharged, etc. For normal conditions and when a substantially conical casing is employed, the aperture is made triangular with its base approximately 0.65 of the maximum diameter of the casing and its apex coincident with the apex of the casing.

In the practical embodiment of the apparatus illustrated by Fig. 2, there are two conical casings 7 :7 in alignment, each having a triangular aperture 8 in its peripheral wall as aforesaid. Impellers 9: 9 are arranged-for rotation, one in each of the casings, being attached to a common shaft 10 journalled in bearings 11:11 secured to the bases of the casings. Said impeller shaft 10 is adapted to be driven from a power source within the 'vessel through a shaft 12 and gears 13:141.

Each impeller 9 is shown as consisting simply of a metal plate slotted and balanced in a centrally disposed rotating boss. It func-. tions as a two-blade fan. Additional blades may, however, be added at the discretion of the designer.

The impeller blades may be given suitable curved shapes which are well known to persons familiar with the art.

The apparatus according to Fig. 2 is intended to be disposed athwartship in a vessel with the apertures 8: 8 in the casings 7 7 open to the surrounding fluid through the bottom of the vessel. When so arranged rotation of the impellers 9:9 causes fluid streams (denoted by the arrows) to flow through the casings, said streams being each in the form of a helix (about the axis of its casing) that expands from the point of inlet to the point of discharge. The direction of discharge is tangential to the helix and substantially fore or aft according to the rotation of the impellers, so that the reactive thrust resulting from the discharge propels the vessel ahead or astern as the case may be. The efflciency astern will obviously equal the efficiency ahead in this apparatus.

Instead of combining two impeller units a plurality of suchunits, each constructed to work on the principle described with refcrnce to Fig. 1, may be disposed along each side of the vessel A as shown diagrammatically in Figs. 3 and 1 where the casings of the units are each represented as of conical form with the axis almost vertical and the apex at the bottom and with their triangular apertures 8 exposed to the fluid through the vessels sides. Rotation of the impellers within the casings 7 causes streams of the fluid surrounding the vessel to flow as expanding helices through the casings, these streams being discharged from the apertures 8 substantially fore or aft according to the direction of rotation of said impellers and creating a combined thrust to propel the vessel ahead or astern.

lVhen the casing is of conical shape with a flat base the normal direction of discharge is tangential to the casing but at an angle to its axis equal to the angle of pitch of the helix. For this reason the casings 7 are inclined to the vertical in Fig. 3 so as to get the discharge in a more nearly true' fore and aft direction. With such an arrangement, however, the propelling efficiency in one direction (astern) is slightly less than the propelling efiiciency in the other direction (ahead), whereas if each of the casings be vertically arranged in the plane of the drawing the efiiciency is equal in both directions. In some cases instead of inclining the axis of each casing for the purpose stated, the base of said casing may be curved or otherwise shaped to deflect the discharge stream in the required direction.

If desired, the casings 7 (Fig. 3) may be incorporated in the vessels structure as part of the hull A, as shown in Fig. 4.

Both forms of the apparatus hereinbefore described are intended for direct reversibility. Where reversibility is required without changing the direction of rotation of the impeller (or impellers) a reversing valve may be fitted to the casing or each casing 7, as shown in Figs. 5 and 6 according to which the valve consists of a flat or curved plate 15 hinged about an axis lying parallel to the peripheral wall of the casing. The flap is carried by a rod 16 journallcd in brackets or plates 17:17 depending from the impeller casing, and it is arranged to be turned from a position inboard through a shaft 18 and gears 19:20. While the flap is in one extreme position the stream of fluid flows through and from the casing in the direction indicated by the full line (Fig. 6), whereas when the flap is in the other extreme position the discharge is deflected in the opposite direction as indicated by the dotted line in that figure. In the first mentioned position the flap or valve presents a continuation of the curvature of the casing resembling a portion of an involute and the fluid leaves the casing in exactly the same manner as when reversing equipment is not fitted. A

neutral position of thrust lies between the ahead and the astern positions of the flap or valve.

The boss 9 of the impeller 9 (Fig. 5) is made hollow and watertight to float the impeller in the fluid Within the casing. This feature can be embodied in any form of the apparatus where saving of weight is important.

Although I have shown reversing equipment applied to a twin unit apparatus intended to be located athwartship in a vessel, it can be applied to the unit or each unit of the apparatus however this may be arranged.

Then a twin unit apparatus is employed and located athwartship in the manner stated, each casing 7 may, as indicated by the dotted line in Fig. 5, be truncated near its apex to coincide with the hull of the vessel A.

From the foregoing it will be apparent that the essence of my present invention is a recess or apertured casing of concentrically expanding form, any number of which may be provided in a vessel, and an impeller rotatable therein to create a helical flow that expands in the direction of its motion and is discharged tangentially to the helix. For the purpose of illustration, I have shown the casing 7 in the form of a cone, but it will now be understood that the casing may consist of a frustum of a cone, a paraboloicl, a

hemisphere, or some other concentrically expanding form in which the required expanding helical flow can be created.

Further, instead of locating the casing or casings of the apparatus within the vessel or incorporating them in the vessels structure as part of the hull, as herein particularly described, the apparatus may be carried outside the hull in the form of an outboard propeller.

Propelling apparatus as herein described is particularly suitable for shallow draught, especially when located wholly within the vessel or incorporated in the vessels structure as part of the hull where it is protected from damage.

For the sake of simplicity I sometimes refer to the creation of one helical stream in each recess or casing of concentrically expanding form, such as would be obtained by a single-bladed impeller, but it is obvious that the flow in each casing will consist actually of one or more helices depending upon the num ber of impeller blades and that when there are two or more helices these interlace without turbulence as in the case of a screw propeller.

The details of construction of the apparatus and the arrangement of the apparatus, or each of the units comprising the same, may be varied without departing from the scope of the invention as defined by the claims that follow.

Having now fully described my invention, what I claim and desire to secure by Letters Patent is 1. Apparatus for propelling a vessel, comprising at least one casing of concentrically expanding form with a tangential inlet and outlet opening, and an impeller rotatable in the casing to create a flow of the surrounding fluid in the form of one or more than one helix that expands in the direction of its motion.

2. Apparatus for propelling a vessel, comprising at least one casing of substantially conical shape with an aperture in its side expanding towards its base, and an impeller of corresponding shape rotatable within the cas- 111g.

3. Apparatus for propelling a vesel, comprising at least one conical casing having a triangular aperture in its peripheral wall to provide an inlet near the apex and an outlet near the base of the casing and an impeller rotatable within the casing.

Propelling apparatus built up of two aligned units each comprising a casing of con centrically expanding form with a tangential inlet and outlet opening, and an impeller rotatable in the casing to create a helical flow that expands in the direction of its motion; and means whereby the two impellers of said units can be rotated from a power source.

5. Propelling apparatus built up of two ali tned units each comprising a casing of concentrically expanding form with a tangential inlet and outlet opening, and an impeller rotatable in the casing to create a helical flow that expands in the direction of its motion; a common shaft for the two impellers of said units; and means whereby said shaft can be rotated from a power source.

In testimony whereof I aflix my signature.

DONALD VIVIAN Ho'rorimss. 

